1. Field of the Invention
The present invention relates to a method for discharging vapor-laden air in a cooking area and a corresponding vapor-discharging device. In addition, this invention relates to a method for operating a vent device.
2. Description of Related Art
Numerous problems that occur in conjunction with treatment of air are known from the state of the art. For the user, such problems are noticeable most clearly and most directly in discharging cooking vapors and/or other kitchen odors, especially in a cooking area, so that this group of problems is of primary concern within the scope of the present invention. However, this is not to exclude other application fields with which those skilled in the art may be familiar, i.e., fields where the situation is similar or special cutting manufacturing machines in factories that are cooled with an oil-in-water emulsion.
In general the problem of having to remove the vapors and/or odors formed in cooking occurs in cooking areas. In addition to a very high water vapor content, these fumes also contain air from which fats and odoriferous substances may be precipitated, among other things. Various methods for discharging air from cooking areas and the corresponding household appliances are known from the state of the art to solve this problem. With household appliances, vent hoods may be differentiated according to two types of function that differ in general: exhaust hoods and circulating hoods. Exhaust hoods filter a large portion of the fat particles contained in cooking vapors out of the vapors and then discharge the air to the outdoors through a duct and a masonry box or similar devices. The effect of such exhaust hoods is good in principle, but installation is often problematical and very complex. Installation is not even possible in many homes, because there is no outside air connection, for example, or it cannot be implemented at a reasonable expense. In the long run, however, such vent hoods may also constrict or even block an exhaust duct such as a chimney due to cooking deposits or may even destroy them due to a buildup of soot.
Circulating hoods first carry the vented air through a fat filter and then through an activated carbon filter and then discharge the air thus conveyed back into a room, in particular back into the kitchen. The effect of such known circulating hoods is unsatisfactory, however, mainly for the following reasons. There is no removal of moisture, so the atmospheric humidity rises rapidly in the kitchen when cooking. Furthermore, elimination of odors by the activated carbon filter is satisfactory for only a short period of time because the activated carbon filter rapidly becomes clogged mainly by fine particles of fat and water molecules not retained by the fat filter. The activated carbon filter therefore becomes ineffective and must be replaced frequently.
A device then operates on a purely mechanical basis for reducing the fat content of air is known from German Utility Model DE 299 03 794 U1, wherein a mechanical separation grid for separating liquid and/or solid particles is proposed; this device is based essentially on the design of a stabilized labyrinth system for improved collection and discharging of fluids. However, the good effect described in DE 299 03 794 U1 is limited essentially to filtering out relatively large fluid and solid particles, but also it produces a loud flowing noise. Functioning is possible only in the so-called “fog range.” However it is impossible to separate moisture from a mixture of air and water vapor using this device.
German Utility Model DE 299 23 124 U1 discloses a device that provides a heat exchanger in a crosscurrent or countercurrent operation with cooling air for condensing the water vapor content out of air. A labyrinth must always be provided upstream from this device to lengthen the respective cooling zone because of the relatively minor temperature difference between the air and the cooling air. With this device, in general the dew point of humid air cannot be reached in general. The water separation effect is inadequate. Furthermore, this approach results in high flowing noises on the one hand while on the other hand also resulting in a very complex internal structure involving problems in production and cleaning.
However, German Patent DE 100 20 205 A1 proposes an active cooling of the air in a vapor vent hood, performed by a heat exchanger (that is protected from icing up) with a regulated refrigeration machine. Providing adequate cooling power without icing up, in particular in a resting position, requires a refrigeration machine with relatively large dimensions in view of the large volumes of air to be handled in such a device. Therefore, this approach has the disadvantage of having a high electric power demand during operation of such a vapor vent hood in addition to its large size.